Previous medical infusion pumps have comprehended a wide variety of methods for pumping fluids into a patient. The most common of these methods has been a peristaltic pump. In a peristaltic pump, a plurality of actuators or fingers serve to massage a parenteral fluid delivery tube in a substantially linear progression. The primary problem associated with peristaltic pumping technology is that the tube is repeatedly deformed in an identical manner, thereby over the course of time destroying the elastic recovery properties of the tube so that the tube maintains a compressed aspect. This destruction of the elastic recovery properties of the tube results in the volumetric output of the pump changing markedly over time. Another common type of pump used in the volumetric delivery of medical fluids is commonly known as a cassette pump. Although cassette pumps do not display the fairly rapid degradation of performance as evidenced in a peristaltic pump, they require a fairly elaborate pump cassette to be integrated with the IV tube. This added expense of having to change a cassette along with an IV set every time an operator wishes to change the medicament delivered to the patient, significantly raises the cost of patient care. Additionally, as both peristaltic and cassette pumps, as well as other infusion devices present in the market, require a fairly elaborate knowledge of the specific pumping device to ensure that the IV set is loaded appropriately, generally medical infusion pumps were purely the purview of the nursing or medical staff in a hospital environment.
The necessity of manually loading a set into an IV pump is universal in the art. Generally when a standard IV set is used, in addition to the rapid degradation of accuracy mentioned above, great difficulty is encountered in correctly loading the set into those pumps presently in the art. The state of the art of loading technology as it relates to medical infusion pumps has progressed only to the state of enclosing the IV tube between a pumping device and a door or cover and adding progressively more elaborate sensors and alarms to assure that the tube is correctly loaded into the pump. Even so, loading errors occur with regularity requiring great efforts on the part of hospital staffs to ensure that critical errors are minimized.
The state of the art in infusion pumps also includes the requirement of manually assuring that a free-flow condition of medicament does not occur when an IV set is installed or removed from a pump. Although hospital staffs exercise great care and diligence in their attempts to assure that free-flow conditions do not occur, a demonstrable need for additional precautions directed to the prevention of a free-flow condition has been a continuous concern of healthcare workers.
U.S. Pat. No. 5,199,852 to Danby discloses a pumping arrangement including a squeezing device for deforming a length of pliant tubing first in one direction locally to reduce its volume, and in another direction tending to restore its original cross-section and on either side of the squeezing device, inlet and outlet valves which operate by occluding the tubing. The control of the valves is by a plurality of motors controlled by a micro-processor.
U.S. Pat. No. 5,151,091 to Danby et al. discloses a pumping device which alternately compresses and reforms a section of tubing.
U.S. Pat. No. 5,055,001 to Natwick et al. discloses an infusion pump with spring controlled valves designed to open at a specific predetermined pressure.
U.S. Pat. No. 3,489,097 to Gemeinhardt discloses a flexible tube pump having a unitary fixture operative to act as an inlet and outlet valve and a pumping body located therebetween, driven off an eccentric.
U.S. Pat. No. 2,922,379 to Schultz discloses a multi-line pump having an inlet and an outlet valve mechanism and a pumping body located therebetween wherein both the inlet valve mechanism and the outlet valve mechanism are driven from a single cam.
U.S. Pat. No. 3,359,910 to Latham discloses a cam driven pump having inlet and outlet valves driven from a single cam and a pump body driven by an eccentric co-rotating with the single cam.
U.S. Pat. No. 4,239,464 to Hein discloses a blood pump having an inlet and outlet plunger serving as valves and a displacement plunger located therebetween.
U.S. Pat. No. 5,364,242 to Olson describes a drug pump having at least one rotatable cam and a reciprocally mounted follower engaged with the cam in a tube which is compressed by the follower during rotation of the cam. In the embodiment disclosed there are three cams.
U.S. Pat. No. 5,131,816 to Brown et al. discloses a infusion pump containing a plurality of linear peristaltic pumps and includes a position encoder mounted on the pump motor shaft to determine when the shaft has reached the stop position in the pump cycle.
U.S. Pat. No. 4,950,245 to Brown et al. discloses a multiple pump which is individually controlled by a programmable controller within the pump.
U.S. Pat. No. 4,273,121 to Jassawalla discloses a medical infusion system including a cassette and a deformable diaphragm and inlet and outlet windows which are occludable to pump the fluid contained in the cassette.
U.S. Pat. No. 4,936,760 to Williams discloses a infusion pump adapted to use a special tube wherein the tube has diametrically opposed handles extending longitudinally thereon and wherein the handles are adapted to be gripped by pump actuators so as to deform the tube transversely by pulling or pushing on the handles.
U.S. Pat. No. 5,092,749 to Meijer discloses a drive mechanism for actuating the fingers of a peristaltic pump having a jointed arm pivotally attached at one end to a drive member and at the other end to a fixed point on the base of the pump and a rotary cam actuator mounted on the base to urge against the arm and reciprocate the drive member.
U.S. Pat. No. 4,850,817 to Nason et al. discloses a mechanical drive system for a medication infusion system comprising a cassette pump wherein inside the cassette a single cam drives the inlet and outlet valves as well as the pump mechanism.
U.S. Pat. No. 5,252,044 to Raines discloses a cassette pump.
U.S. Pat. No. 3,606,596 to Edwards discloses a drug dispensing pump.
U.S. Pat. No. 3,518,033 to Anderson discloses an extracorporeal heart.